Sunshine duration and global radiation trends in Italy (1959–2013): To what extent do they agree?

Manara, Veronica; Brunetti, Michele; Maugeri, Maurizio; Sánchez-Lorenzo, Arturo; Wild, Martin

doi:10.1002/2016jd026374

Cited by 24 publications

(15 citation statements)

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“…A direct comparison of observed‐derived R s (with 44 pairs of stations) reveals consistent trends during the periods of dimming (−1.11 W/m 2 per decade versus −1.38 W/m 2 per decade from 1961 to 1980) and brightening (1.51 W/m 2 per decade versus 1.47 W/m 2 per decade from 1980 to 2009) in Europe (Figure b and Table ), further suggesting that SunDu‐derived R s data can accurately reproduce the observed trends in Europe from 1961 to 2009. This seems to be inconsistent with Manara et al (), who showed substantial differences in the trends between the SunDu and R s in Italy during the dimming period but similar trends during the brightening period. Simultaneously, they considered that the observed SunDu and R s data have different sensitivities for different climatic conditions, especially in the dimming period.…”

Section: Resultscontrasting

confidence: 85%

“…Simultaneously, SunDu is almost free from influences of instrument replacement (Stanhill & Cohen, ). Even though, SunDu data do not provide a direct estimate of R s and have the different sensitivity of atmospheric turbidity changes, compared with R s observations, they are still a good proxy for variations of R s (Manara et al, ). Moreover, existing studies have shown that SunDu‐derived R s estimates roughly depict long‐term variability in R s almost without the problems associated with early radiometry mentioned above (K. Wang, ; K. Wang et al, ) and reflect to some extent impacts of both aerosols and clouds (Tang et al, ; K. Wang, Dickinson, et al, ).…”

Section: Introductionmentioning

confidence: 99%

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A Revisit of Global Dimming and Brightening Based on the Sunshine Duration

Wang

Zhou

et al. 2018

Geophysical Research Letters

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Observations show that the surface incident solar radiation (R s ) decreased over land from the 1950s to the 1980s and increased thereafter, known as global dimming and brightening. This claim has been questioned due to the inhomogeneity and low spatial-temporal coverage of R s observations. Based on direct comparisons of~200 observed and sunshine duration (SunDu) derived R s station pairs, meeting data record lengths exceeding 60 months and spatial distances less than 110 km, we show that meteorological observations of SunDu can be used as a proxy for measured R s . Our revised results from~2,600 stations show global dimming from the 1950s to the 1980s over China (À1.90 W/m 2 per decade), Europe (À1.36 W/m 2 per decade), and the United States (À1.10 W/m 2 per decade), brightening from 1980 to 2009 in Europe (1.66 W/m 2 per decade) and a decline from 1994 to 2010 in China (À1.06 W/m 2 per decade). Even if 1994-2010 is well known as a period of global brightening, the observed and SunDu-derived R s over China still exhibit declining trends. Trends in R s from 1923 to 1950 are also found over Europe (1.91 W/m 2 per decade) and the United States (À1.31 W/m 2 per decade), but the results in Europe may not well represent the actual trend for the European continent due to poor spatial sampling.Plain Language Summary Ground-based observations of the surface incident solar radiation (R s ) reveal the phenomena known as global dimming and brightening, that is, a downtrend over land from the 1950s to the 1980s and an uptrend thereafter. However, R s observations suffer from inhomogeneity issues and low spatial-temporal coverage. Sunshine duration-derived R s is not present above problems and was utilized here to compare with observed R s from China, Europe, and the United States over the 1950-2010 common period. Results show a good agreement between two data sets except for the dimming period in China, mainly due to instrument sensitivity drift of R s observations. Therefore, using more extensive sunshine duration-derived R s data set at approximately 2,600 stations over China, Europe, and the United States since 1901, a revisit of global dimming and brightening has been reasonably conducted, including the early period prior to the 1950s.

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Section: Resultscontrasting

confidence: 85%

Section: Introductionmentioning

confidence: 99%

A Revisit of Global Dimming and Brightening Based on the Sunshine Duration

Wang

Zhou

et al. 2018

Geophysical Research Letters

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“…As the resultant trends of SD and DTR, compared with the SSR trend, diverged in the second period for São Paulo, in all sky conditions, caution might be taken when those variables are used as proxies to downward surface solar radiation in the context of dimming and brightening analyses. This study revealed that different factors may act on each variable, leading to a distinct behavior, as also mentioned by Manara et al (2017).…”

Section: Discussionsupporting

confidence: 65%

Fifty-six years of Surface Solar Radiation and Sunshine Duration at the Surface in São Paulo, Brazil: 1961–2016

Yamasoe

Rosário

Almeida

et al. 2020

Preprint

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Abstract. Fifty-six years (1961–2016) of daily surface downward solar irradiation, sunshine duration, diurnal temperature range and the fraction of the sky covered by clouds in the city of São Paulo, Brazil, were analyzed. The main purpose was to contribute to the characterization and understanding of the dimming and brightening effects on solar global radiation in this part of South America. As observed in most of the previous studies worldwide, in this study, during the period between 1961 up to the early 1980's, more specifically up to 1983, a negative trend in surface solar irradiation was detected in São Paulo, characterizing the occurrence of a dimming effect. A similar behavior, a negative trend, was also observed for sunshine duration and the diurnal temperature range, the three variables in opposition to the trend in the sky cover fraction. However, a brightening effect, as observed in western industrialized countries in more recent years, was not observed. Instead, for surface downward irradiation, the negative trend persisted and still in consonance to the cloud cover fraction increasing trend. The trends for sunshine duration and the diurnal temperature range, by contrast, changed signal. Some possible causes for the discrepancy were discussed, such as the frequency of fog occurrence, urban heat island effects, aerosol changes and greenhouse gas concentration increase. Future studies on aerosol effect are encouraged, particularly with higher temporal resolution as well as modeling studies, to better analyze the contribution of each possible causes.

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“…Furthermore, the surface observed sunshine duration data that were used for estimating DSR (Wang, 2014;Yang et al, 2006) were not available over the TP until the 1960s. Regardless, the statistical model can hardly capture the low aerosols' influence on surface solar radiation by sunshine duration because sunshine duration has a lower sensitivity than DSR to atmospheric turbidity changes that is estimated by aerosol optical depth (AOD) (Manara et al, 2017). Thus, considering that remote sensing has been developed for several decades, it provides a valuable opportunity to employ satellite observations to monitor spatiotemporal variations at regional scales.…”

Section: Introductionmentioning

confidence: 99%

Air pollution slows down surface warming over the Tibetan Plateau

et al. 2020

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Abstract. The Tibetan Plateau (TP) plays a vital role in regional and global climate change. The TP has been undergoing significant surface warming starting from 1850, with an air temperature increase of 1.39 K and surface solar dimming resulting from decreased incident solar radiation. The causes and impacts of solar dimming on surface warming are unclear. In this study, long-term (from 1850 to 2015) surface downward radiation datasets over the TP are developed by integrating 18 Coupled Model Intercomparison Project phase 5 (CMIP5) models and satellite products. The validation results from two ground measurement networks show that the generated downward surface radiation datasets have a higher accuracy than the mean of multiple CMIP5 datasets and the fused datasets of reanalysis and satellite products. After analyzing the generated radiation data with four air temperature datasets, we found that downward shortwave radiation (DSR) remained stable before 1950 and then declined rapidly at a rate of −0.53 W m−2 per decade, and that the fastest decrease in DSR occurs in the southeastern TP. Evidence from site measurements, satellite observations, reanalysis, and model simulations suggested that the TP solar dimming was primarily driven by increased anthropogenic aerosols. The TP solar dimming is stronger in summer, at the same time that the increasing magnitude of the surface air temperature is the smallest. The cooling effect of solar dimming offsets surface warming on the TP by 0.80±0.28 K (48.6±17.3 %) in summer since 1850. It helps us understand the role of anthropogenic aerosols in climate warming and highlights the need for additional studies to be conducted to quantify the influence of air pollution on regional climate change over the TP.

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Sunshine duration and global radiation trends in Italy (1959–2013): To what extent do they agree?

Cited by 24 publications

References 100 publications

A Revisit of Global Dimming and Brightening Based on the Sunshine Duration

A Revisit of Global Dimming and Brightening Based on the Sunshine Duration

Fifty-six years of Surface Solar Radiation and Sunshine Duration at the Surface in São Paulo, Brazil: 1961–2016

Air pollution slows down surface warming over the Tibetan Plateau

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